How to make water flow from the certain areas of an object?
It's better to use a special object to be the emitter, by duplicating the part of the mesh you need the fluid to emitt from Shift + D your selection in edit mode, then  P and choose "Selection" to separate the mesh to a new object, assign the particles to the new object, position your vertices were you want the water to emitt. 
You can use "Vertices" option instead of "Faces" in the Particles Tab parameters, Under "Emission" panel > "Emit From:". Remember to uncheck the "Emitter" check box if you don't want the emitting object to show in render.

Edit: Adding images for better explanation.